This invention relates generally to forage harvesters and more particularly to those including a floating attachment.
Crop harvesting attachments are removably connected to harvesting machines such as forage harvesters. It is desirable to have the attachment "float" along the ground surface. This is accomplished by tensioning a spring or springs to a desired preload so that most of the weight of the attachment is suspended and only a fraction of the actual weight of the attachment rests on the ground. Thus, the effective ground engaging weight of the attachment is minimized. One of the reasons this is advantageous is because the ground surface is uneven and impact loads are forced on the attachment. Such impact loads could cause structural damage if the impact encountered the full weight of the attachment. However, since the impact encounters only a fraction of the actual weight of the attachment, damage is minimized. Another reason this is advantageous is because it is quite obviously easier to move the attachment along the ground when its effective ground engaging weight has been minimized.
A limitation of known attachment flotation is that the amount of flotation preload decreases rapidly as the attachment is either forced upwardly or is raised mechanically. This limitation occurs because the spring is usually relaxed as the attachment moves upwardly. The situation is compounded since the torque about the attachment pivot point is increased due to the attachment CG moving away from the pivot point. As a result, when the attachment is only a few inches above the ground surface, its effective ground engaging weight is significantly increased.
The foregoing illustrates limitations of the known prior art. Thus, it is apparent that it would be advantageous to provide an alternative directed to overcoming one or more of the limitations as set forth above.